Power operated rotary mowing and edging devices are well known in the prior art. Thus, for example, one such device is disclosed in U.S. Pat. No. 3,680,639 of Davis. The device of the Davis patent is stated to be useful as an edger and trimmer for use around embedded lawn sprinkler heads. The Davis device--and the other prior art rotary mowing and edging devices-- suffer from several distinct disadvantages. In the first place, they are generally quite bulky and heavy and are difficult to carry over substantial distances and on hilly areas and inclines; they thus are not very suitable for trimming around the many sprinklers heads found on large golf courses. In the second place, such prior art devices are often expensive to purchase and operate. In the third place, such prior art devicers are often relatively slow.
In the past several years, a new class of rotary trimming devices has emerged. These devices, known as string trimmers and brushcutters, are often commonly referred to as "weedeaters." These string trimmers are high speed, inexpensive devices.
The string trimmer and brushcutter devices are not suitable for readily trimming around sprinkler heads. One could utilize such devices to cut around the periphery of the sprinkler head with these devices, but this would take an inordinate amount of time. Furthermore, the string device does not clear dirt and grass from the area around the outside diameter of the sprinkler head as efficiently as, e.g., a U-shaped blade would do so.
In order to provide a new sprinkler head trimming device by replacing the string cutting apparatus of the "weedeater" with a U-shaped cutting blade. Several problems are presented by this approach. If the blade is too heavy, then the relatively small motor of the "weedeater" will not be able to rotate it at high speeds. If the blade is too light, it will not have the physical properties required to maintain its dimensional stability and its cutting edge. If, as desired, the "weedeater" is operated at high speeds in order to maximize productivity, then the U-shaped blade is likely to flare and bend and, thus, become unacceptable for further use.
It is an object of this invention to provide a blade assembly which can readily be incorporated into a "weedeater" assembly, which can be operated at high speeds by the drive mechanism of the "weedeater" assembly, which when operated at such high speeds does not undergo a substantial amount of flaring and/or bending, and which, in conjunction with said assembly is especially suitable for trimming sprinkler heads on golf courses.